A variety of medical devices have been developed for endovascular repair. For instance, various methods and devices have been developed to repair aneurysmal or occluded branches of the aorta. Many such devices include tubular introducers having internal passages, sometimes referred to as introducer catheters, that include a seal and/or valve to retard or stop blood flow through their internal passages. For instance, introducer catheters are known to employ Captor™ valves. Introducers are typically designed to track along a guide wire and some introducers are designed to seal against both small diameter guide wires and larger diameter portions of delivery devices.
Existing introducers and their seals/valves suffer a number of shortcomings. For instance, they leak blood more than is desirable. With some devices, this can be exacerbated or caused by storage before use. This is because seals are subject to “taking a set” or being deformed during prolonged storage. Where seals are deformed during storage, they may take a significant period of time to (or never) recover their optimum condition.
Another characteristic of many existing introducers and their seals or valves is the level of both static and dynamic sliding friction that resists relative movement between the introducers and delivery devices passing through them. In many applications it may be desirable to minimise or at least provide a low level of static and/or dynamic friction so as to assist a surgeon with fine manipulations of a delivery device passing through an introducer.
There is a need to minimise blood leakage through introducers, especially blood leakage around guide wires used in endovascular procedures. There is also a need to provide introducers that facilitate easy manipulation of delivery devices passing through them.
Throughout this specification, the term “distal” with respect to a portion of the aorta, a deployment device or an endograft means the end of the aorta, deployment device or endograft further away in the direction of blood flow from the heart and the term “proximal” means the portion of the aorta deployment device or end of the endograft nearer to the heart in the direction of blood flow. When applied to other vessels, similar terms such as caudal and cranial should be understood.